Effect of carboxylic acid groups on the supercapacitive performance of functional carbon frameworks derived from bacterial cellulose

Abstract Three-dimensional (3D) carbonaceous materials derived from bacterial cellulose (BC) has been introduced as electrode for supercapacitors in recent. Here, we report a simple strategy for the synthesis of functional carbon frameworks through 2,2,6,6-tetramethylpilperidine l-oxyl radical (TEMPO) −mediated oxidation of bacterial cellulose (BC) followed by carbonization. TEMPO-mediated oxidation can efficiently convert the hydroxyls on the surface of BC to carboxylate groups to improve electrochemical activity. Because of its high porosity, good hydrophilicity, rich oxygen groups, and continuous ion transport in-between sheet-like porous network, the TEMPO-oxidized BC delivers a much higher gravimetric capacitance (137.3 F/g) at low annealing temperature of 500 °C than that of pyrolysis BC (31 F/g) at the same annealing temperature. The pyrolysis modified BC obtained at 900 °C shows specific capacitance (160.2 F/g), large current stability and long-term stability (84.2% of its initial capacitance retention after 10,000 cycles).